DIY big props for coaxials

I opened this topic to support those who want to experience the construction of larger propellers for the f3p models.
In a few hours you can build a set of propellers using only materials available frequently in the workshop or at home.
Method used is an older one but the materials are secret ...who would have thought?...depron propellers?
So I started doing the first tests and I drew and cut a 15-inch propeller blade that I sanded and laminated with thin fiberglass and i found that it is strong enough to just 1 gram weight.
After that I built the first complete propeller to figure out what and how...the good news is that resisted at high speed rpm ,bad news ..is a bit heavy 3,5g because i added too much epoxi .
I rebuilt the procedure and I was more careful with resin and so i got a 0.9g blade... this makes me think that it is possible to have a total weight of 2.5 g for one prop.
I hope the pictures will help you understand how simple it is .
For the moment i don*t have at home carbon fiber tissue but in the future i will try if needed.
The central part is a little cross for mounting tiles cutted and drilled.

Images

If you use it with this motor,, http://www.hobbyking.com/hobbyking/s...Outrunner.html
you must set an end point for throttle and set low pitch for 12 to 13 inch props,for larger props 14 -15 inch you must change the gear ratio by usig the 40 teeth crown gears with 8 teeth pinion
Now i use a smaller motor but not tested yet with larger props.
Like i said before the hub is a square profile piece of plastic cutted and drilled.

Images

These are just the first tests, I think to experience v -shape props in order to short the coaxial shafts and i*ll try the criss-cross bandage with carbon fiber for the props.
There is a lot of space to improve.
These are the tools...hope you like the mold

I too am well down the rabbit hole seeking the lightest/strongest F3P props. I have yet to find a better solution than contest balsa. These are hand made (pretty east if you use CAD to help layout). 13" @ 1.66g and still way stronger than it needs to be from hub to root. Probably could get to 1.2'ish. The other one is denser balsa, weighs a gram more way stronger than it needs to be everywhere. I may thin it some more. I think Kimmo posted one at less than a G. I have some Rohacell on the way to try similar to yours Bicutz

Bill, great stuff. Are you willing to share your CAD files? Understood if you want to keep them proprietary. Our little team here is interested in both balsa and milled cores.

RED

Quote:

Originally Posted by bill clark

I too am well down the rabbit hole seeking the lightest/strongest F3P props. I have yet to find a better solution than contest balsa. These are hand made (pretty east if you use CAD to help layout). 13" @ 1.66g and still way stronger than it needs to be from hub to root. Probably could get to 1.2'ish. The other one is denser balsa, weighs a gram more way stronger than it needs to be everywhere. I may thin it some more. I think Kimmo posted one at less than a G. I have some Rohacell on the way to try similar to yours Bicutz

Hi Vince!
Yes is 3mm depron and 1,5mm carbon rod for about 70mm long, try to insert the rod along the line before sanding work and without cut the blade ..this will save some weight. ....plastic bag, polyethylene i think...something like servo bags .